1. Field of the Invention
The present invention relates to an apparatus and process for magnetising a magnetisable material. In one form the invention relates to a process for inducing magnetism into a flow stream of particulate material to facilitate subsequent separation of some of the magnetised material and will primarily be described with reference to this context. It should be remembered, however, that the process of the invention may have broader use in systems not involving the subsequent separation of any of the magnetised material, such a general particulate settling and water clarification process.
2. Description of the Related Art
Devices for inducing a magnetic field into a magnetisable particulate suspension are known in the art and have been applied to coagulate fine particles. Prior to entering a settling tank for separation, such a particulate suspension can be passed through a vessel in which a magnetic field is applied. The magnetisable particles become magnetised and subsequently self-attracted. These self-attracted particles may then settle under the influence of gravity to the bottom region of the tank faster than they would have done as individual particles, without any need to use chemical coagulant or flocculation reagents. Such a process is useful for removing very fine particulates which generally do not separate quickly or easily under the influence of gravity.
The apparatus for such a process commonly makes use of a low gradient magnetic field having a small rate of change of magnetic strength. This type of magnetic field reduces the tendency of the magnetised particles to move toward the poles of the magnet/s that are used to create the magnetic field.